The subject matter of the instant invention relates to a method and composition obtained by contacting a tertiary amine with at least one inert gas. The tertiary amine composition can be used, for example, to produce polyurethane foam having reduced missions.
Tertiary amines are commonly used as catalysts for the preparation of polyurethane materials that are widely used in consumer durable goods (such as cars, home appliances, furniture, toys, among other products) as well as in insulation of commercial and residential areas. Minimization of chemical emissions in these applications is of key importance to eliminate potential exposure of workers and end users to the hazards associated by either adventitious contaminants or by-products produced by adventitious contaminants that may be present in some of the raw materials utilized in the preparation of polyurethane based products. Controlling the presence of undesired contaminants in the raw materials utilized to make polyurethane catalysts is an ongoing challenge because removal of very small amount of impurities from these raw materials is extremely difficult to achieve using conventional separation methods such as chromatography, distillation or recrystallization. Most of these techniques if successfully applied will require extensive labor and time making these methods in many instances cost prohibited. During the preparation of polyurethane foam several components are used such as polyol, isocyanates, surfactants, blowing agents, crosslinkers, cell openers, pigments, fillers, fire retardants, metal catalysts and tertiary amine catalysts. In some cases, certain tertiary amines may contain very small amounts (ppm levels) of contaminants such as formaldehyde and dimethylformamide (DMF). The concentration of these contaminants may increase over relatively long periods of time depending on the storage conditions.
Conventional methods for removing undesired contaminants are disclosed in the following patents. Referring now to one of those patents, U.S. Pat. No. 4,801,426 relates to a method to de-odorize malodorous aliphatic amines by flushing the amine with nitrogen gas at about 30 to 100° C. to remove odorous compounds. The method is conducted on higher aliphatic amines containing long aliphatic chains in the range from C8 to C40.
U.S. Pat. No. 7,879,928 discloses a process for preventing the formation of aldehydic compounds in polyether polyols, polyester polyols, or polyurethanes by the incorporation of an effective amount of a phenolic antioxidant and an aminic antioxidant. The process relies upon the addition of chemicals to the polyols or polyurethanes as well as aminic compounds that can also decompose or create undesired emissions from finished products.
U.S. Pat. No. 7,169,268 discloses a process for providing tertiary amine products which are color stable and have greatly reduced tendency to take on color during their storage. The process relies on the addition of ethylene diamines to the distillation pot prior to or during the distillation of the tertiary amine product. This process does not address the formation of color-free contaminants such as dimethylformamide or formaldehyde during storage. Instead, the process is limited to minimizing or reducing color bodies formation overtime that are caused by the presence of impurities in the tertiary amines that can potentially be scavenged by the ethylenediamine prior or during their distillation.
US2008/0269382 discloses a process for stabilizing organic materials. However, this process does not address the long term stability of a polyurethane additive such as a tertiary amine. Also, the process depends on the addition of new chemicals to the polyurethane formulation which may cause additional undesired emissions.
US2009/0088489 discloses a reactive amine catalyst and in particular diethylaminoethoxyethanol and/or diethylethanolamine in aqueous or organic solutions for use in producing flexible polyurethane foam. However, this disclosure does not address the problem of how to prevent the formation of toxic chemicals such as dimethylformamide and formaldehyde on already existing amine catalysts.
US2011/0009512 relates to tertiary amine catalysts useful in the production of polyurethane foam. However, this disclosure does not address the issue of tertiary amine storage as well as minimization or reduction of dimethylformamide.
WO11084865 discloses a method to reduce the formation of DMF and formaldehyde of samples exposed to air using amine oxidation inhibitors such as free radical scavengers and/or antioxidants to prevent the oxidation of the amine. The disadvantage of the method is that requires the addition of new chemicals to the tertiary amine which may bring additional environmental, health and safety issues to both the tertiary amine as well as to the finished product.
The previously described patent applications, patents and other documents are hereby incorporated by reference.
There is a need in this art for a tertiary amine composition having relatively low amounts of undesired contaminants and for a method to produce an amine composition that is stable during storage and does not form such contaminants.